Final answer:
Commercial fur class color classifications are black (dark) colored and light colored (pastel), with medium colored as an additional classification. The genetics of Labrador retriever fur color demonstrates epistasis, where the E and B alleles determine if the fur color will be yellow, black, or chocolate. Similarly, in food coloration, the FDA classifies colors as subject to certification or exempt from certification, with the latter category including natural pigments.
Step-by-step explanation:
The two color classifications for a commercial fur class are black (dark) colored and light colored (pastel), and sometimes a third classification for medium-colored fur is noted. Labrador retrievers provide a clear example of how fur color is genetically determined, showcasing a form of gene interaction known as epistasis, where one gene can mask the expression of another gene. In Labradors, the E allele controls the expression of the B allele; the ee genotype results in a yellow lab, the B_E_ genotype gives a black lab, and the bbE_ genotype results in a chocolate lab.
Furthermore, in the food industry, the US FDA's classifications for permitted colors are divided into ones that are subject to certification, which generally refers to synthetic dyes and those that are exempt from certification, which includes natural pigments derived from vegetables, minerals, or animals. Exempt colors are often more costly, can impart additional flavors, and generally are regarded as more natural compared to certified colors. Examples of exempt colors include annatto extract, dehydrated beets, caramel, beta-carotene, and grape skin extract.